1. Field of the Invention
This invention relates to repair of hernias and similar defects in the tissues of humans and animals, and in particular to a laparoscopic hernia repair method and a synthetic patch used therefor. The patch is manipulated in the body cavity of the patient and is attached to connective tissues, by engaging the patch at a plurality of peripheral punch holes preliminarily formed in the patch.
2. Prior Art
A hernia is a weakening of the musculofascial tissues defining the structural wall of a body cavity such as the abdomen, resulting in a gap through which tissues can protrude. Typically a sac is formed confining the tissues at the musculofascial defect, which sac protrudes from the plane of the tissue wall. There is a possibility of constriction of the neck of the sac, and life-threatening infection if untreated.
A weakening or separation of the musculofascial tissues due to any cause can develop into a hernia. For example scarring from a previous incision or other trauma of the abdominal wall can develop into a hernia, or a hernia can form at the site of a passage through the musculofascial tissue, the passage becoming enlarged, for example, due to pressure of the viscera during muscular exertion. There are various forms of hernias, the inguinal hernia being a common example wherein the abdominal viscera and peritoneal sac protrude through the floor of the inguinal cavity at the point where the musculofascial tissue is relatively weakened due to the passage of the spermatic duct (in males) or the femoral blood vessels and the round ligament (in females). Another common site of a hernia is the passage of the umbilical cord. Hernias can also develop in the diaphragm, and elsewhere. In general similar problems occur wherever visceral tissues are abutted against a confining wall of tissue which, when weakened for whatever reason, permits the tissues to protrude through the confining wall, where the tissues become subject to constriction and infection or exert potentially dangerous pressure on tissues beyond the wall.
Hernias have been repaired surgically by suturing across the musculofascial defect to draw the opposite sides of the defect together, the sutures bridging across the defect. However, such a repair is not suitable at hernias occurring at the site of a passage for ducts, blood vessels or the like. Moreover, pulling the sides of the defect inwardly results in tension on the musculofascial tissue via the sutures. The site of the sutures defines a weakening of the tissue and leads to a high rate of recurrence of the hernia at the sutured edge of a previous repair.
According to one technique for repairing hernias, tension on the site is reduced by inserting a plug into the opening, for example of rolled polypropylene screen, to reduce the tension applied by the sutures to the musculofascial tissue surrounding the defect, while blocking protrusion of the sac. According to another technique, a patch having sufficient strength to resist the tendency of the sac to protrude is placed over the defect and sutured to the musculofascial tissue. This technique also avoids tension on the musculofascial tissues and has been shown to be successful in minimizing recurrence of the hernia. Various materials have been used in experimental or clinical hernia repairs, including for example polypropylene mesh, Dacron fabric, tantalum gauze, and the like.
Recently, patch repairs of this type have been made using expanded polytetrafluoroethylene or Teflon. The expanded polytetrafluoroethylene (PTFE) form of patch has proved advantageous because it elicits a low foreign body reaction, does not encourage infection, is low in adhesion formation, and does not erode into the abdominal viscera.
Most importantly for permanent repair of hernias, the PTFE material supports fibrous tissue incorporation. Fibroblast intrusions into the porous expanded PTFE material of the patch tend to engage the patch securely as the repair heals. Over time the fibroblasts are replaced by collagen, merging the patch into the surrounding tissue to form a permanent structural repair. An expanded PTFE patch material is available from W. L. Gore & Associates, Inc., Medical Products Division, Flagstaff, Ariz., under the trademark Gore-Tex.
Whereas the hernia originates in the abdominal cavity, laparoscopic diagnosis and repair of hernias is advantageous as it allows repair of the hernia from inside the abdomen without further damage to the musculofascial tissue containing the defect. Laparoscopic hernia repair presents minimal risk, and initial recurrence rates are acceptable for short term follow up. However, the operation is difficult because suturing via trocars and similar laparoscopic instruments, particularly in the inguinal area, requires a great deal of expertise. Although needles and needle holders for use in this manner are available, it is very important to strictly follow an exacting suturing procedure, and normally takes a relatively long time. For example, the surgeon may spend as long as five minutes in setting a single suture.
Hernia repairs have been undertaken by laparoscopic techniques using surgical staples such as the endo-clip, via a clip applicator or surgical stapler. Although there is a risk that a clip can become dislodged, the laparoscopic clip or staple applier facilitates introduction of the clips or staples, and avoids much of the time and difficulty associated with suturing. It would be possible to attach a patch material such as expanded PTFE using surgical staples. The major difficulty remaining in the laparoscopic hernia repair operation is then to position the patch and fasten the patch in place using properly placed clips or staples.
It is important that the patch be accurately positioned in order to fully bridge across the defect to form a good structural repair. In certain instances such as the repair of inguinal hernias at the passage of the spermatic duct or round ligament, the problem is complicated by the need to leave clearance for the duct or ligament, and the need to avoid damage thereto. Obstruction or constriction of the spermatic duct will affect the fertility of the patient. Interference with the round ligament or femoral blood vessels can affect circulation and/or mobility. Accordingly, care must be taken to accommodate the passage while providing a structural bridge across the passage that does not damage or adhere to the tissues passing through.
The present invention modifies the known expanded PTFE patch to facilitate placement and attachment. The patch is provided with a series of punch holes, preferably all around the periphery at an approximate spacing from the edge equal to the span of the surgical staples, and of a diameter approximating the width of one limb of the clip or staple applicator This limb of the applicator engages the patch in the peripheral punch holes, making it readily possible to attach the patch to ligamentous tissues at one point and then to spread the patch over the defect by engaging the applicator in an opposite punch hole. The surgeon thus proceeds to place clips or staples around the periphery of the patch. For inguinal hernia repairs the spermatic duct or round ligament passes under the patch at a punch hole, or two adjacent punch holes, left unfastened.
The invention is useful for laparoscopic patch repairs generally, and is especially useful in connection with hernia repair including inguinal, femoral, diaphragmatic and the like.